POLICE in the worst knife crime areas of Britain, including Birmingham, will be told to prosecute anyone found carrying a blade, Prime Minister Gordon Brown said today.

He said carrying knives or guns was "completely unacceptable" and that officers should not be looking at cautions for offenders.

The zero-tolerance applied will be applied to 12 knife crime hotspots, mainly in large cities like London, Manchester, Liverpool as well as Birmingham.

"We have to send out a message and reinforce it with action," he said. "It is completely unacceptable to carry a knife or a gun. Where police have previously been cautioning people, there now has to be a presumption of prosecution."

He also expressed worries about violent computer games featuring knives.

"No-one wants censorship or an interfering state," he said.

"But the industry has some responsibility to society and needs to exercise that."

His intervention follows rising concern about knife crime on British streets.

There has been a string of knife-related deaths recently, including teenagers Nassirudeen Osawe in Islington, north London, and Jack Large in Grange Hill, Essex.

Mr Brown said: "You cannot be casual or cool about knives.

"Society cannot cope with people carrying guns and knives and threatening to use them.

"There are boundaries you cannot cross and one is this country's zero-tolerance on knives."